Telemetry means for tissue stimulator system

In combination with a living tissue stimulator system comprising an implantable tissue stimulator and an external receiving means, a telemetry system comprising:

• a first oscillator located in said external receiving means;
• an impedance creating circuit comprising a first inductor coupled to said first oscillator and partially determinative of said first oscillator signal characteristics;
• an impedance reflecting circuit comprising a second inductor in magnetically coupled relationship to said first inductor and located in said implantable tissue stimulator;
• a voltage controlled oscillator having an output frequency related to a signal to be telemetered;
• and
• control means for altering impedance characteristics of said impedance reflecting circuit in relation to said voltage controlled oscillator output voltage, thereby altering said first oscillator signal characteristics.

In combination with a living tissue stimulator system comprising an implantable tissue stimulator and an external receiving means, an FM/FM telemetry system comprising:

• a first oscillator located in said external receiving means;
• an impedance creating circuit comprising a first inductor coupled to said first oscillator and partially determinative of said first oscillator frequency;
• an impedance reflecting circuit comprising a capacitor and a second inductor in magnetically coupled relationship to said first inductor and located in said implantable tissue stimulator;
• a voltage controlled oscillator having an output frequency related to a signal to be telemetered;
• and
• control means for altering impedance characteristics of said impedance reflecting circuit in relation to said voltage controlled oscillator output voltage, thereby altering the output signal frequency of said first oscillator.

In combination with a living tissue stimulator system comprising an implantable tissue stimulator and an external receiving means, an FM/AM telemetry system comprising:

• a first oscillator located in said external receiving means;
• an impedance creating circuit comprising a first inductor coupled to said first oscillator;
• an impedance reflecting circuit comprising a resistor and a second inductor in magnetically coupled relationship to said first inductor and located in said implantable tissue stimulator;
• a voltage controlled oscillator having an output frequency related to a signal to be telemetered;
• and
• control means for altering impedance characteristics of said impedance reflecting circuit in relation to said voltage controlled oscillator output voltage, thereby altering the output signal amplitude of said first oscillator.

In combination with an implantable device for humans having an impedance reflecting circuit and an external receiving means, a telemetry system comprising:

• means for altering the impedance of said impedance reflecting circuit in relation to a signal to be telemetered from said device, said impedance reflecting circuit comprising a first inductor;
• a second inductor in magnetically coupled relationship to said first inductor;
• and
• said external receiving means comprises impedance sensing means connected to said second inductor for providing an output signal responsive to impedance changes in said impedance reflecting circuit, said output signal being related to said signal to be telemetered.